Branch drain sizing

1) The '06 IPC, if I interpret table 110.1 and 110.2 correctly, states: a lav is worth 1 unit, a kitchen sink w/disposer and dishwasher is worth 2, and a clothes washer is worth 2. All combined, that's 5, and a 2" branch line can handle up to 6 units. Do I understand this correctly and Are these numbers the same for the '09 IPC?

2) The iron I'm replacing has no clean-out and there is no practical place that I can put it. (In fact, local plumbers are frequently seen stuffing cable down vents.) Can I extend my branch beyond the fixtures and install a horizontal, overhead clean-out? I didn't notice anything in the '06 that would prevent it.